1. Field of the Invention
The present invention relates to a breeding aquarium equipped with a water purifying filter, and more particularly, to a breeding aquarium having a filter chamber therein.
2. Description of the Prior Art
In a conventional breeding aquarium equipped with a filtering chamber therein, known as the flow-down type one, the water lifted by an air pump flows down vertically through the filter material or medium housed in the filtering chamber. This type of aquarium has the advantage that since the water passing through the filter material contains air or oxygen resolved therein or mixed therewith, it is favorable to the propagation of filtering fungi which have the function of purifying water. However, this known aquarium has the disadvantage that the size of the breeding chamber is relatively small, otherwise the size of the overall arrangement becomes large. If, to overcome this disadvantage, the size of the filter chamber is made small, another disadvantage arises that not only the filtering capacity is reduced, but also the filter material must be frequently regenerated.
A bottom filtering type of aquarium is also known. However, this type of aquarium has the disadvantage that since the surface of the filter medium is exposed to the breeding chamber, sewage directly contacts the filter medium to stop it up. The stopping up of the filter medium causes the reduction of the amount of water passing through the filter medium, resulting in the shortage of oxygen to be supplied to filtering fungi and at the same time the generation of anaerobic bacteria, so that the purifying ability is reduced.
An aquarium is also known in which aquatic plants are also accessorily coltured therein. However, the thickness of the earth for planting is required to be 5 cm or more, so that if the filter layer is utilized for planting in the flow-down type of aquarium, the passage of water is obstructed by the plants. If exclusive planting earth is provided instead of utilizing the filtering medium or material as the planting earth, water does not flow through the earth because of its large thickness of 5 cm or more, thus adversely affecting the growth of plants and resulting in root rot. The root rot is a source of sewage in the aquarium.